Research in the Molecular Pathogenesis is focused on defining changes in the genes that underlie inherited susceptibilities to common diseases such as cancer and birth defects. Currently under investigation are the inherited breast and ovarian cancer genes, BRCA1 and BRCA2. These proteins appear to be involved in DNA repair. Previously, we discovered which proteins specifically interact with BRCA1. We also have found that BRCA1 is important for controlling the expression of other genes and is plays a role in DNA repair. Additional experiments under this project have revealed that BRCA1 appears to help in the process of recognizing and eliminating cells that may progress to form tumors. We now know that the increase in breast, ovarian and prostate cancer risk associated with genetic variants in these genes is due to a failure of these mutated proteins to function in the DNA repair pathway. We are now collaborating on a project designed to understand the molecular changes that occur in ovarian tumors. A large percentage of ovarian tumors occur in women who carry mutations in their BRCA1 or BRCA2 genes. We have recently identified changes in genes that may be associated to the formation of in ovarian tumors. These changes can now be related to specific clinical outcomes and responses to treatment. In the past, we applied a bioinformatics approach to probe the role that genomic structure may play in protein evolution. The study of the BRCA1 and BRCA2 genes has led us to discover a new connection between a specific type of gene structure and evolutionary rates of changes. This observation appears to be generalizable to almost any gene and holds true across all metazoan lineages. We recently completed the study of all the exons in each of six genomes. The rules we observed for our smaller sample have been confirmed in this larger set. This section created and maintains a database of mutations in the breast cancer genes, BRCA1 and BRCA2, this scientific resource is used by investigators through out the word. In the past year we have added information to the database that will allow users to assess the clinical and functional significance of mutations. As an extension of the database, we are working on methods to determine which mutations in BRCA1 and BRCA2 are of medical significance.